COMPOUNDING HOTLINE

FEBRUARY 01, 2005

Martin A. Erickson, III, RPh

Q: Can you suggest a formulation or approach for the preparation
of an oral suspension of omeprazole?

A: For the past few years, pharmacists have used the Reflux
Solutions products ChocoBase and CaraCream to compound
suspensions of proton pump inhibitors such as omeprazole. These
products were discontinued in December 2004. Omeprazole
(Zegerid from Santarus) 20-mg powder for oral suspension was
released in October 2004. The company states that the formulation
is based on patents licensed from the University of Missouri expiring
in July 2016. Santarus also announced that it would release a
40-mg packet in the first quarter of 2005. Pharmacists should use
commercially prepared New Drug Application (NDA) or Abbreviated
New Drug Application (ANDA) products when they are available
for patient therapy. In some cases, however, patient-specific, documented
medical/therapeutic occurrences may require extemporaneous
compounding, such as patient intolerance to a particular
ingredient in the NDA or ANDA ("commercial") product.

Prior to the availability of ChocoBase and CaraCream, published
studies indicated long-term shelf stability of omeprazole in 8.4%
sodium bicarbonate solution. Subsequent clinical studies indicated
that sodium bicarbonate 8.4% might not provide adequate buffer
capacity to overcome stomach acidity, resulting in variable bioavailability
due to the instability of omeprazole in acid. The information
supported the use of ChocoBase and CaraCream, for which studies
seemed to indicate greater "protection" of the omeprazole, presumably
from oils in the formulations. Other studies indicate that an
increase in the alkalinity of the formulation can provide adequate
buffer for therapeutic effectiveness of an extemporaneously compounded
formulation of omeprazole suspension, but alkaline solutions
create compliance difficulties because of taste.

Because the studies of the bioavailability of omeprazole
extemporaneously compounded in oral suspension conflict, it
seems reasonable to employ this formulation when necessary: